...Marlow¹

Present Address: University of Pennsylvania, Dept. of Physics and Astronomy, 209 S. $33^\mathrm{rd}$ Street, Philadelphia, PA 19104-6396, U.S.A.

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...it

The definition of both is flat-spectrum between L-band and C-band, i.e. $\alpha\gt-0.5$ where $s_{\rm f}\sim f^{\alpha}$, the essential difference being the lower flux density limit of 200mJy for JVAS and 30mJy for CLASS. However, since CLASS is defined based on newer catalogues (GB6 and NVSS: Gregory et al. 1996; Condon et al. 1998) than JVAS, there will be some essentially random differences due to differing quality of observations and variability of the sources. All the JVAS lenses mentioned in Table 1 are in the new CLASS sample, which, having no upper flux density limit, subsumes JVAS. The previous samples CLASS-I and CLASS-II will be similarly subsumed in the same sense as JVAS, though the differences here will be slightly larger since bands other than L and C were used in the preliminary definition of these samples.

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